Epoxidized vegetable oils



EPOKZDIZED VEGETABLE OlLS Stanley P. Rowland, Philadelphia, and RichardF. Conyne, Andalusia, Pa, assignors to Rohm & Haas Company,Philadelphia, 1 21., corporation of Delaware No Drawing. ApplicationJuly 15, 1953 Serial No. 368,236

Claims. (Cl. 260348) This invention relates to epoxidized vegetable oilsand to their preparation and use;

An object of this invention is to provide epoxidized oils which havesuperior properties when employed as plasticizers for such plasticmaterials as vinyl resins, nitrocel ulose and chlorinated rubber.

Another object is to prepare epoxidized oils which are not onlyextremely compatible with a wide range of plastics but which give riseto very stable compositions.

These and other objects are achieved by hydrogenating an epoxidizedvegetable oil until the degree of residual unsaturation of the oil isreduced to the point Where it is equal toor preferably less thanthatrepresented by an iodine number of three.

Currently large quantities of plastic articles are made from plasticizedcompositions containing polyvinyl chloride, polyvinyl acetate,copolymers of vinyl chloride and vinyl acetate, p'olyvinylidenechloride, polyvinyl butyral, nitrocellulose and chlorinated rubber. Itis common practice to use epoxidized oils as plasticizers in thepreparation of such plastic materials as'isevident from sales literatureand U. S. Patents 2,556,145 and 2,559,177. The epoxidized oils in turnare made by treating vegetable oils with peracids, typified by performicand peracetic acids, as shown, for example, in U. S. Patents 2,458,484,2,485,160 and 2,569,502. While such plasticized compositions havegenerally good properties, they do, nevertheless, sufi'er from at leastone deficiency which limits their use, namely that they often becometacky and subsequently dirty when they are exposed to light and heat.For instance, when such compositions are merely placed near a window fora period of weeks, they become sticky and at the same time they retaindust which falls upon them. Frequently they also become stiller. Theseobjectionable properties are believed to result from a gradual spewingor migration of a part of the plasticizer to the surface of thecomposition.

An object, therefore, of this invention is to provide improvedepoxidized oils which have little, if any, tendency to behave in thisway so that more stable plastic compositions can be made for use in sucharticles as curtains, draperies, upholstery, luggage, handbags and thelike.

it has now been found that epoxidized oils which have a relatively highcontent of oxirane oxygen, or epoxy oxygen, together with a very lowdegree of residual unsaturation are far superior as plasticizers to theepoxidized oils prepared heretofore, all of which had definitely moreresidual unsaturation. The combination of high content of oxiraue oxygenand almost complete saturation is responsible for the enhancedcompatibility-stability characteristics of the products of thisinvention.

These improved oils are made by hydrogenating an epoxidi'zed oil whichhas an oxirane oxygen-content of at least 4.5% and preferably one above5.5%, whereby the double bonds in the oil become saturated at least tothe point where the iodine number of the oil is reduced to a maximumvalue of three and preferably to a value of about 2,822,368 we 71 F 1 15 one. 'During hydrogenation there is a tendency for the epoxy groupsalready present in the oil to change to hydroxyl groups. And while someof this conversioncan be tolerated, it is important to keep it at aminimum because, although the stability of the plastic composition onaging is dependent upon the reduction of the unsaturation of the oil,the original compatibility of the 'epoxidized oil is directlyproportional to its oXirane oxygen-content.

The epoxidized oils which are hydrogenated by the process of thisinvention are themselves prepared by the methods described in thepatents listed above. It is essential that the oils contain at least4.5% oxirane oxygen before hydrogenation and actually it is preferredthat they contain at least 5.5 During hydrogenation, the oxiraneoxygen-content'is usually reduced about 0.3 to 0.4%. That is, an oilcontaining 5.7% oxirane oxygen before hydrogenation contains about 5.4%oxirane oxygen after hydrogenation. Therefore, in order to end with anoil having a minimum oxirane oxygen-content of 5.0 it is best to startwith an oilhaving an oxirane oxygen content of about 5.3-5.5%.

The efiic'iency of thehydrogenati-on process depends upon severalinter-related factors which can be varied over reasonably wide limits.

Excellent results have been obtained with Raney'nickel, finely dividedplatinum and finely divided palladium as catalysts. The latter twocatalysts are more etfective at low temperatures and in lowerconcentrations than the Raney nickel. Thus, veryra pid hydrogenation ofthe double bonds in epoxidized oils takes place, in the presence of onlya fraction of one percent noble metal based on the oil, at room orambient temperatures. With the use of these catalysts the temperaturesmay even be lowered to about 0 C. if desired. In the case ofRaney'nickel, it is preferred to use higher temperatures narnelythosefrom about 50 C. to about 100 C. Intact, with Raney nickel the rate of"hydrogenation is unnecessarily sluggish below about C.

.As higher temperatures arelen ployed; there is anincreasingly greatertendency for the epoxy groups to .be degraded or to be reduced tohydroxyl groups and accordingly the lowest temperatures, consistent withreasonable speed of saturation of the double bonds, are recommended.Tempe'ratures'up to 150 C. have been employed with Raney nickel as acatalyst but those-below C. are preferred and those above C. are bestavoided.

As little as 0.1% palladium or platinum catalyst based on the oil iseflective. Higher amounts of Raney nickel, starting at about 1% andgoing as high as about 20%, are recommended. p

Ordinarily solvents for the oils are employed and these also exert someinfluence on the rate of hydrogenation. Hydrocarbons such as heptane andiso-octane, which are readily removed from the product, are suitable.Lower alcohols are lik'ewiserecommended, particularly since they permitthe use of smaller amounts of catalysts.

The pressure of hydrogen also influences the rateof hydrogenation andwhile pressures of less than one atmosphere have been employed withpalladium or platinum as the catalyst, higher pressures-ordinarily often or more atmospheres-are recommended when Raney nickel is used. Theuppermost pressure in any case is limited only by the convenience andsafety of operation.

Rocking hydrogenation bombs, autoclaves, Paar shakers and gasdispersion'units have been used. I

The following epoxidized oils containing at least 4.5% oxirane oxygenhave been converted by hydrogenation to essentially saturated productshaving oxirane oxygen-contents of at least 4.0%: epoxidizedsoybean,corn, cotton seed, safflower, sunflower,- sesame, poppyseed,,walnutahdpeanut oils. 7

The following examples serve to illustrate the prepa- Several portionsof an epoxidized soybean oil, prepared by the process of U. S. Patent2,485,160 using performic acid and containing 5.81% oxirane oxygen andhaving an iodine number of 20, were hydrogenated in a stainless steelrocking bomb. To the oil was added 10% Raney nickel and the hydrogenpressure was maintained at 10001200 pounds per square inch (p. s. i.).After the reaction was complete, the bomb and contents 4 EXAMPLE InTable II are listed the reactants, conditions of reaction and theanalyses of the products obtained by hydrogenating, under a variety ofconditions, an epoxidized soybean oil made according to the process ofU. S. Patent 2,485,160 with performic acid and having an oxiraneoxygen-content of 5.8% and an iodine number of 17. The pressures ofhydrogen are expressed in pounds per square inch (p. s. i.) and thepercentages of catalyst and solvent are based on the weight of the oilbeing hydrogenated.

Table II Temp, Hydro- Time In Percent Percent Iodine Run No. Apparatus0. gen Hours Raney Percent Solv. Oxirane N um- Pressure Ni. Oxygen berPaar Shaker, 70-80 30 1. 75 17 50 Isooctane... 5. 50 2. 4 Rocking Bomb84-87 295 1.0 17 d 5. 47 1.3 Gas Difluser 50 i 15 4. 17 5. 56 3.0 o 75 i15 2. 0 17 5. 18 2. 6 75 15 2.0 17 5.31 2.0 70-80 190 2.0 2 5. 7 2. 270-80 45 4.5 A 17 50 Isooctane 5.0 1.0 70-80 1,790 1.0 1.7 do 6.3 0.175-80 190 2.5 do 5.5 1.0 75-80 90 2.75 5 -do 5.7 2.3 70-80 90 2. 5 2 50Ethanol 5. 6 2.1 70-80 4.0 2 o 5.5 2.8

were allowed to cool slowly to room temperature. The EXAMPLE 3 followingis a tabulation of the reactants, conditions of operation and thephysical properties of the products obtained.

Thermoplastic compositions were prepared in the form of sheets 'byfluxing and milling at 325 F. the following materials:. 60 parts ofpolyvinyl chloride (Geon 101); 40 parts of an epoxidized oilplasticizer; 1 part of tribasic lead sulfate as a stabilizer; and 0.5part of stearic acid as .amold lubricant. Samples of the individualhydrogenated oils prepared above were compared, in the role of the oilplasticizer, with the original epoxidized oil which had not beenhydrogenated. The composition containing the non-hydrogenated oil servedas control. Specimens of all of thecompositions were tested side-by-sidein a Fade- O-Meter at a temperature of 110 C. Other specimens of thecompositions were exposed to ordinary daylight by being placedside-by-side on the interior sill of a window at room temperature. Inthe Fade-O-Meter test the control composition containing thenon-hydrogenated oil became excessively tacky in 45 hours, showed adefinite spewing in 106 hours, and stiifened badly and cracked in 289hours, whereas the compositions containing the hydrogenated oils showedonly the slightest spewing in 312 hours and did not crack until 757hours had passed. The control sample on window exposure-developed adefinite tackiness in 15 days, showed definite spewing in 35 days,definite stiffening in 87 days, and after 270 days was extremely stiffand dirty. Under the same conditions, the compositions containing thehydrogenated oils gave no evidence of spewing or stiffening in at least270 days. They had clean surfaces and were considered to be essentiallyunchanged.

An epoxidized soybean oil was prepared by the procedure described inExample 4 of U. S. Patent 2,485,484. In this process, 292 parts ofperacetic acid solution (prepared from glacial acetic acid and 30% H 0was treated with 18.3 parts of sodium acetate trihydrate. Then 50 partsof soybean oil was added and the reaction mixture was vigorouslyagitated for 3 /2 hours at 35 C. The isolated oil had an oxiraneoxygen-content of 5.4%, an iodine number of 16 and a viscosity of 2.4poises. This oil dissolved in its own weight of isooctance was thenhydrogenated in a rocking bomb at 75-80 for 2 hours with hydrogen at apressure of p. s. i. in the presence of 17% Raney nickel. The resultantproduct, freed of solvent, had an oxirane oxygen-content of 5.2%, aniodine number of 1.1, and a viscosity of 2.6 poises.

EXAMPLE 4 Sailiowerseed oil was epoxidized by the process of U. S.Patent 2,569,502 by reacting safllowerseed oil with peracetic acid at 20C. The product had an iodine number of 16, a viscosity of 2.25 poisesand contained 6.0% oxirane oxygen.

The oil was next hydrogenated under the same conditions as are describedin Example 3, immediately above, and the resultant product had an iodinenumber of 1.0, a viscosity of 3.2 poises and contained 5.74% oxiraneoxygen.

EXAMPLE 5 A sample of linseed oil was epoxidized by the process of U. S.Patent 2,485,160 using one mole of H 0 for each double bond in each moleof the oil. The product which had an oxirane oxygen-content of 7.4%, aniodine number of 28 and a viscosity of 4 poises was then hydrogenatedunder conditions identical with those described in Example 3 above. Thefinal isolated oil then had an oxirane oxygen-content of 7.1%, an iodinenumber of 2 and a viscosity of 4 poises.

EXAMPLE 6 Soybean oil was'epoxidized by the process of U. S. Patent2,485,160 using formic acid and H 0 The latter reagent was employed in aratio of only 0.7 mole per double bond in each mole of oil with theresult that a product was obtained which contained only 4.6% oxiraneoxygen and which had an iodine number of 40. This epoxidized oil wasthen hydrogenated by the process of Example 3 aboveand gave rise to aproduct which contained 4.31% oxirane oxygen and had an iodinenumber of2.7. The advantage of the hydrogenated oil over the original oil in itscompatibility-stability characteristics whenincorporated into polyvinylchloride was striking.

EXAMPLE 7 An epoxide cottonseed oil was prepared by the followingprocess which has been recommended as a commercially feasible method.(Bulletin #16 entitled Epoxidation and Hydroxylation with HydrogenPeroxide and Peracetic Acid, published July 12, 1950, December 19, 1950,and March 1952, by Buffalo Electro-Chemical Company, Inc., Buffalo, NewYork): A solution of 30 grams of anhydrous sodium acetate and 498 gramsof 40% peracetic acid was added slowly to 550-grams of cottonseedoil'while the latter was vigorously agitated. One-third of the peraceticacid solution was added over a period of 30 minutes while thetemperature was maintained at 20 C. and the remainder was added over thenext 30 minutes while the temperature was held at 25 C. The reactionmixture was stirred at C. for 4 hours, after which it was poured into500 ml. of a saturated NaCl solution. The oil layer was separated andwashed repeatedly'with saturated salt solution until it was free ofacid. It was then dried with anhydroussodium sulfate and filtered. Theproduct had an oxirane oxygen-content of 5.1% and an iodine number of12.

This oil was next hydrogenated by the process described in Example 3above and the final product had an iodine number of 1.3 and contained4.76% oxirane oxygen.

EXAMPLE 8 A modification of the method described in Example 7 wasfollowed in preparing epoxidized linseed oil. A total of 294.8 grams of40% peracetic acid in acetic acid containing 10 grams of anhydroussodium acetate was added over a period of 45 minutes to 270 grams oflinseed oil held at 20-23 C. In this case the ratio of peracetic acid tolinseed oil was equivalent to about 0.78 mole for every double bond ineach mole of oil. The mixture was stirred at 20 C. for one hour afterwhich the oil was shaken with 277 grams of ice-water. After removal ofthe aqueous phase, the oil was diluted with 200 grams of toluene and thesolution was washed three times with 200 ml. portions of a saturatedaqueous solution of sodium sulfate. The oil was then separated and nextstripped of toluene and water at 100 C./25mm. The filtered product hadan oxirane oxygen-content of 6.3% and an iodine number of 51.

When this oil was hydrogenated by the process of Example 3 above thefinal product had an iodine number of 2 and contained 6.06% oxiraneoxygen.

EXAMPLE 9 A second sample of epoxidized linseed oil was prepared by thegeneral process of Example 7 above, employing, however, a 41% excess ofperacetic acid over that amount required by theory to convert all of thedouble bonds to epoxy groups. Thus, 536 grams of 40% peracetic acidcontaining 18 grams of sodium acetate was added over a period of 45minutes to 270 grams of linseed oil and the mixture was then stirred for2 hours at 26-27 C. The oil, after being washed and filtered, contained8.1% oxirane oxygen and had an iodine number of 6. This material wasnext hydrogenated by the process of Example 3 above with the result thatan oil was obtained which had an iodine number of 2 and an oxiraneoxygencontent of 7.6%.

The above examples serve to show how relatively unsaturated epoxidizedoils which have been prepared by a variety of methods can be convertedto essentially saturated epoxidized oils. It is to be further noted thatin every instance the hydrogenated oil had much more satisfactorycompatibility-stability characteristics than the epoxidized oil fromwhich'it was made. That is to say',#

dized oils at low temperatures and under low pressures The productsprepared in this way have the same advantages of compatibility andstability which characterize the materials prepared with Raney nickel athigher temperatures and higher pressures.

EXAMPLE 10 A solution of 500 parts of the same epoxidized soybean oilemployed in Example 2 above in 250 partsof isooctane was placed in aPaar shaker, and to it was added 50 parts of a platinum-on-carboncatalyst containing 5% metallic platinum. Hydrogen was admitted under apressure of 15 p. s. i. After 15 minutes the absorption of hydrogenappeared to be complete but the reaction wasallowed to continue for 15minutes more. The product,

after being isolated from the catalyst and solvent had an oxiraneoxygen-content of 5.27% and an iodine number of 0.6.

The above procedure was followed with the one exception that apalladium-on-carbon catalyst, in the same. amount and containing thesame percentage of palladium,

was substituted forthe platinum catalyst. Results were essentiallyidentical with those described above and the product had an oxiraneoxygen-content of 5.4 and an iodine number of 0.6.

It is apparent from these results that the process of hydrogenation canbe carried out batch-wise or by a continuous process.

We claim:

1. As a new composition of matter an epoxidized vegetable oil which hasan oxirane oxygen-content of at least 5.0% and also has a degree ofunsaturation which is represented by an iodine number of about one.

2. As a new composition of matter epoxidized soybean oil which has anoxirane oxygen-content of at least 5.0% and also has a degree ofunsaturation which is represented by an iodine number of about one.

3. As a new composition of matter epoxidized corn oil which has anoxirane oxygen-content of at least 5.0% and also has a degree ofunsaturation which is represented by an iodine number of about one.

4. As a new composition of matter epoxidized saffiowerseed oil which hasan oxirane oxygen-content of at least 5.0% and also has a degree ofunsaturation which is represented by an iodine number of about one.

5. As a new composition of matter epoxidized cottonseed oil which has anoxirane oxygen-content of at least 5.0% and also has a degree ofunsaturation which is represented by an iodine number of about one.

6. A process for the preparation of an epoxidized vegetable oil havingan oxirane-oxygen content of at least 4.0% and a degree of unsaturationno greater than that represented by an iodine number of one whichcomprises treating by agitating in the presence of hydrogen and of ahydrogenation catalyst, at a temperature from 0 to C., an epoxidizedvegetable oil which has an oxirane-oxygen content of at least 4.5%,continuing treat ment of the vegetable oil until the degree ofunsaturation of said oil is no greater than that represented by aniodine number of one and an oxirane-oxygen content of at least 4.0%,terminating hydrogenation, and separating the epoxidized vegetable oilproduct.

7. A process for the preparation of an epoxidized vegetable oil havingan oxirane-oxygen content of at least 4.0% and a degree of unsaturationno greater than that represented by an iodine number of three whichcomprises treating by agitating in the presence of hydrogen and of ahydrogenation catalyst, at a temperature from to 150 C., an epoxidizedvegetable oil which has an oxirane-oxygen content of at least 4.5continuing treatment of the vegetable oil until the degree ofunsaturation of said oil is no greater than that represented by aniodine number of three and an oxirane-oxygen content of at least 4.0%,terminating hydrogenation, and separating the epoxidized vegetable oilproduct.

I 8. The process of claim 7 in which the vegetable oil is soybean oil.

9. The process of claim 7 in which the vegetable oil is corn oil.

10. The process of claim 7 in which the vegetable oil is safflower seedoil.

11. The process of claim 7 in which the vegetable oil is cottonseed oil.

12. A process for the preparation of an epoxidized vegetable oil havingan oxirane-oxygen content of at least 4.0% and a degree of unsaturationno greater than that represented by an iodine number of three whichcomprises treating an epoxidized vegetable oil which has anoxirane-oxygen content of at least 4.5% by agitating it in the presenceof hydrogen and in the presence of a hydrogenation catalyst at asuper-atmospheric pressure of 10 to 2,000 p. s. i., at a temperaturefrom 0 to 150 C., continuing treatment under said conditions until thedegree of unsaturation of said oil is no greater than that representedby an iodine number of three and an oxiraneoxygen content of at least4.0%, decreasing the pressure to atmospheric pressure, terminatinghydrogenation, andseparating the epoxidized vegetable oil product.

r 13. A process for the preparation of an epoxidized vegetable oilhaving an oxirane-oxygen content of at least 4.0% and a degree ofunsaturation no greater than that represented by an iodine number ofthree which comprises treating an epoxidized vegetable oil which has anoxirane-oxygen content of at least 4.5% by agitating it in the presenceof hydrogen, a hydrogenation catalyst, and a solvent selected from thegroup consisting of hydrocarbon solvents and lower monohydric aliphaticalcohols'at a temperature of 0 to C., continuing treating under saidconditions until the degree of unsatura tion of said oil is no greaterthan that represented by an iodine number of three and an oxirane-oxygencontent of at least 4.0%, terminating hydrogenation, separating thecatalyst and the solvent, and recovering the epoxidized vegetable oilproduct.

14. The process of claim 13 in which the hydrogenation is' carried outunder a super-atmospheric pressure of 10 to 2,000 p. s. i.

15. The process of claim 13 in which the hydrogenation catalyst is Raneynickel.

References Cited in the file of this patent UNITED STATES PATENTSHeinanen: Suomen Hemistilehti 16B: (Chem. Abstr. 39240516).

1. AS A NEW COMPOSITION OF MATTER AN EPOXIDIZED VEGETABLE OIL WHICH HAS AN OXIRANE OXYGEN-CONTENT OF AT LEAST 5.0% AND ALSO HAS A DEGREE OF UNSATURATION WHICH IS REPRESENTED BY AN IODINE NUMBER OF ABOUT ONE.
 6. A PROCESS FOR THE PREPARATION OF AN EPOXIDIZED VEGETABLE OIL HAVING AN OXIRANE-OXYGEN CONTENT OF AT LEAST 4.0% AND A DEGREE OF UNSATURATION NO GREATER THAN THAT REPRESENTED BY AN IODINE NUMBER OF ONE WHICH COMPRIES TREATING BY AGIATING IN THE PRESENCE OF HYDROGEN AND OF A HYDROGENATION CATALYST, AT A TEMPERATURE FROM 0 TO 150*C., AN EPOXIDIZED VEGETABLE OIL WHICH HAS AN OXIRANE-OXYGEN CONTENT OF AT LEAST 4.5%, CONTINUING TREATMENT OF THE VEGETABLE OIL UNTIL THE DEGREE OF UNSATURATION OF SAID OIL IS NO GREATER THAN THAT REPRESENTED BY AN IODINE NUMBER OF ONE AND AN OXIRANE-OXYGEN CONTENT OF AT LEAST 4.0%, TERMINATING HYDROGENATION, AND SEPARATING THE EXPOXIDIZED VEGETABLE OIL PRODUCT. 